Okay, Dwight. I've been thinking about this all day and I think I've got it.
You need a sheet of film with even density of 0.15 cut into 20 strips of
whatever width you like - let's say 1". Then let's make each step 1/4" wide
so then we cut the 1" wide strips into pieces of 1/4, 1/2, 3/4, 1, 1 1/4, 1
1/2, 1 3/4, 2, ..., and 5". There are only 20 because for step 1 (which
approximates unexposed film base) we'll use a piece of 0.05 density. Here is
a diagram:
---- 21
-------- 20
----
-------- 19
--------
-------- 18
------------
-------- 17
----------------
-------- 16
--------------------
-------- 15
------------------------
-------- 14
----------------------------
-------- 13
--------------------------------
-------- 12
------------------------------------
-------- 11
----------------------------------------
-------- 10
--------------------------------------------
-------- 9
------------------------------------------------
-------- 8
----------------------------------------------------
-------- 7
--------------------------------------------------------
-------- 6
------------------------------------------------------------
-------- 5
----------------------------------------------------------------
-------- 4
--------------------------------------------------------------------
-------- 3
------------------------------------------------------------------------
-------- 2
----------------------------------------------------------------------------
-------- 1
Not only would this would this provide a step-wedge of 21 increments of 0.15
density, it would be shaped like a wedge as well with 1 film thickness on
one end and 21 on the other which would make it about 1/4" thick. This
probably wouldn't work to well if you print with a diffuse light source.
:-o
We could use this wedge as a "master" from which to make as many single
layer step-wedges as we need. Choose a film/developer combination that
yields as near to a straight line response as possible with minimal base
density (maybe TMX developed in Tmax RS which has a long straight line with
no shoulder to speak of and very little toe). Figuring out exposure and
development times will be the hard part.
If anyone tries this, let us know if it works.
Cyantifically yours,
Keith